Laser ablation polymeric materials are receiving increasing attention as substrates for microfluidic devices. Polymers possess a range of chemical, physical, and surface properties that allow great flexibility in matching materials to specific device applications. The cost of polymer substrates also can be significantly less than that of glass or silicon. In addition, fabrication of microchannels in polymer substrates is relatively simple and a greater variety of channel geometries, including complex 3-D systems, can be achieved in comparison to glass and silicon substrates.
There are many techniques employed for the fabrication of microchannels in polymer substrates including imprinting, etching, casting, and injection molding. While these methods are easily implemented, they require fabrication of a template, mask, or mold, otherwise known as a master. The creation of a master is time-consuming and adds an additional step to the microchannel fabrication process. Moreover, minor modifications to the design of a microchannel device require the fabrication of a completely new master.
To circumvent these problems, laser ablation of polymer substrates has been investigated as a method for forming microchannels for rapid proto-typing of different microfluidic geometries. Another potential feature of laser ablation is the capability of surface modification of channel walls concurrent with microchannel formation. However, conventional laser ablation is limited in the sense that it is incapable of forming closed microchannels, being only able to realize open channels and cavities.